Advanced in-situ particle detection system for semiconductor substrate processing systems

ABSTRACT

An FI having an in-situ particle detector and a method for particle detection therein are provided. In one aspect, the FI includes a fan, a substrate support, a particle detector, and an exhaust outlet. The fan, substrate support, and particle detector are arranged such that, in operation, the fan directs air towards the exhaust outlet and over a substrate on the substrate support to create laminar flow. The particle detector, positioned downstream from the substrate support and upstream from the exhaust outlet, analyzes the air and detects particle concentration before the particles are exhausted. The collected particle detection data may be combined with data from other sensors in the FI and used to identify the source of particle contamination. The particle detector may also be incorporated into other system components, including but not limited to, a load-lock or buffer chamber to detect particle concentration therein.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.15/793,458, filed Oct. 25, 2017; which claims benefit of U.S.Provisional Patent Application Ser. No. 62/429,508, filed on Dec. 2,2016; both of which are herein incorporated by reference in theirentirety.

BACKGROUND Field

Aspects disclosed herein relate to systems and methods for semiconductormanufacturing, and more specifically to systems and methods for in-situparticle detection.

Description of the Related Art

In semiconductor manufacturing, a clean, contamination-free processingenvironment contributes to maximizing overall process yield. This isparticularly true as substrate circuitry and geometries shrink to ananometer (nm) scale since particles become more likely to cause defectsand yield loss. Particle detection in each of the processingenvironments within the processing system, including the factoryinterface (FI), helps reduce or eliminate particle contaminants in thesystem. Conventional particle detection methods for the FI include useof a handheld particle detection device.

One problem with the use of a handheld particle detection device is thatdetection only occurs when the FI is open, for example, at initialinstallation or during preventative maintenance. Additionally, since theparticle detection readings are infrequent, identifying the source ofthe particle contamination and troubleshooting the problem takes a greatamount of time, during which the system is down and other sensors in theFI may not be operating.

Therefore, there is a need for improved systems and methods for particlemonitoring in an FI.

SUMMARY

An FI having an in-situ particle detector and a method for particledetection therein are provided. In one aspect, the FI includes a fan, asubstrate support, a particle detector, and an exhaust outlet. The fan,substrate support, and particle detector are arranged such that, inoperation, the fan directs air towards the exhaust outlet and over asubstrate on the substrate support to create laminar flow. The particledetector, positioned downstream from the substrate support and upstreamfrom the exhaust outlet, analyzes the air and detects particleconcentration before the particles are exhausted. The collected particledetection data may be combined with data from other sensors in the FIand used to identify the source of particle contamination for moreefficient troubleshooting. The particle detector may also beincorporated into other system components, including but not limited to,a load-lock or buffer chamber to detect particle concentration therein.

In one aspect, a factory interface is disclosed. The factory interfaceincludes a fan, a substrate support positioned downstream from the fan,a particle detector coupled to an inner surface of the factory interfaceand positioned downstream from the substrate support, a particledetector tube coupled to the particle detector and open to a locationwithin the factory interface, and an exhaust outlet positioneddownstream from the particle detector.

In another aspect, a particle detection system is disclosed. Theparticle system includes a particle detector positioned downstream froma fan and a substrate support in a factory interface, a server connectedto the particle detector, the server being connected to one or moreadditional sensors positioned in the factory interface and beingconfigured to collect particle concentration data from the particledetector and the one or more additional sensors in the factoryinterface, and a network coupled to the server, the network beingconfigured to communicate particle concentration data to one or moreequipment operators.

In yet another aspect, a method for in-situ particle detection in asemiconductor manufacturing system is disclosed. The method includesreceiving a substrate in a factory interface through a factory interfacedoor, transferring the substrate from the factory interface to atransfer chamber or a process chamber through a load-lock slit door,transferring the substrate from the transfer chamber or the processchamber to a substrate support in the factory interface through theload-lock slit door, and continuously monitoring particle concentrationin the factory interface during the transferring the substrate from thefactory interface to the transfer chamber or the process chamber throughthe load-lock slit door and from the transfer chamber or the processchamber to the substrate support in the factory interface through theload-lock slit door.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentdisclosure can be understood in detail, a more particular description ofthe disclosure, briefly summarized above, may be had by reference toaspects, some of which are illustrated in the appended drawings. It isto be noted, however, that the appended drawings illustrate onlyexemplary aspects and are therefore not to be considered limiting ofscope, as the disclosure may admit to other equally effective aspects.

FIG. 1 is a substrate processing system, according to an aspect of thedisclosure.

FIG. 2 is a cross-sectional view of an FI having in-situ particledetection capabilities, according to an aspect of the disclosure.

FIG. 3 is a process flow of continuous, in-situ particle detection in anFI of a semiconductor manufacturing system, according to an aspect ofthe disclosure.

FIG. 4 is a graph of particle concentration detected by a particledetector in an FI over time.

FIG. 5 is a particle detection system, according to an aspect of thedisclosure.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures. It is contemplated that elements and features of one aspectmay be beneficially incorporated in other aspects without furtherrecitation.

DETAILED DESCRIPTION

An FI having an in-situ particle detector and a method for particledetection therein are provided. In one aspect, the FI includes a fan, asubstrate support, a particle detector, and an exhaust outlet. The fan,substrate support, and particle detector are arranged such that, inoperation, the fan directs air towards the exhaust outlet and over asubstrate on the substrate support to create laminar flow. The particledetector, positioned downstream from the substrate support and upstreamfrom the exhaust outlet, analyzes the air and detects particleconcentration before the particles are exhausted. The collected particledetection data may be combined with data from other sensors in the FIand used to identify the source of particle contamination for moreefficient troubleshooting. The particle detector may also beincorporated into other system components, including but not limited to,a load-lock or buffer chamber to detect particle concentration therein.

FIG. 1 is a substrate processing system 100 according to an aspect ofthe disclosure. As shown in FIG. 1, a pair of front opening unified pods(FOUPs) 102 supplies substrates that are received by robotic arms 104from a factory interface 103 and placed into a low-pressure holding area106 before being placed into one of the substrate processing chambers108 a-108 f. A second robotic arm 110 may be used to transport thesubstrates from the low-pressure holding area 106 to the substrateprocessing chambers 108 a-108 f and back. Substrate processing chambers108 a-108 f may include one or more system components for depositing,annealing, curing and/or etching a film formed on the substrate.

FIG. 2 is a cross-sectional view of an FI 203 having in-situ particledetection capabilities. The FI 203 may be used in place of the FI 103 inFIG. 1. The FI 203 includes a fan 210, a filter 220, a substrate support230, load-lock slit doors 240 a, 240 b, an FI door 250, a particledetector 260, a particle detector tube 270, a first substrate holder andeffector robot 280 a, a second substrate holder and effector robot 280b, and an exhaust outlet 290. The FI 203 optionally further includessensors, including but not limited to, fan speed sensors and/or pressuresensors (not shown). Each of the aforementioned components is generallycoupled to one or more walls of the FI 203 by any suitable couplingmeans. For example, the particle detector 260 can be coupled to one ormore walls of the FI 203 by a bracket manufactured to couple theparticle detector 260 to the particular FI. The FI 203 may also includefurther components, such as a cooling station below the substratesupport 230.

In the aspect of FIG. 2, the fan 210, substrate support 230, andparticle detector 260 are arranged in a vertical configuration. Morespecifically, the fan 210 is disposed in an upper portion of the FI 203and is configured to direct air downward through an opening positionedbeneath the fan 210 (not shown), through the filter 220 to a lowerportion of the FI 203, the substrate support 230 is positioned below thefan 210, and the particle detector 260 is positioned below the substratesupport 230. The substrate support 230 includes a multi-bladed supportstructure having openings therebetween to facilitate airflow verticallywithin the FI. The particle detector 260 may be positioned any suitabledistance below the substrate support 230, such as several inches belowthe substrate support 230, for example between about 1 and about 24inches, such as between about 5 and about 15 inches. The substratesupport 230 is also positioned proximate to and between the firstsubstrate holder and effector robot 280 a and the second substrateholder and effector robot 280 b. While FIG. 2 shows a verticalconfiguration, other configurations in which the substrate support 230is positioned downstream from the fan 210 and the particle detector 260is positioned downstream from the substrate support 230, such as ahorizontal configuration, are also contemplated herein. Otherconfigurations include arrangements in which the relative locations ofthe fan 210, the substrate support 230, the particle detector 260, andthe exhaust outlet 290 provide suitable results.

The filter 220 acts as a first barrier to prevent particle contaminationin the FI 203. The filter 220 is generally any suitable filter, forexample, a porous plate of plastic material having pores sized torestrict downward directed flow of particles into the FI 203. The filter220 facilities removal of particles from air or other gases directeddownward by the fan 210.

The particle detector 260 is a remote detector for detecting particlesas small as about 50 nm up to particles as large as about 25 micrometers(μm). One example of a particle detector 260 is a scattered laserdetector. The particle detector 260 generally includes a pump fordrawing air from the environment within the FI 203 into the particledetector 260, a sensor for analyzing the sample air, a laser, and adetector of scattered laser. The particle detector 260 further includesat least one particle detector tube 270 for introducing air into theparticle detector 260. FIG. 2 shows a single particle detector tube 270;however, the particle detector 260 generally includes any suitablenumber of particle detector tubes 270 disposed in any suitableconfiguration. In the example shown in FIG. 2, the particle detectortube extends upward from an upper surface of the particle detector 260towards the fan 210. The laser and the detector are positioneddownstream of the particle detector tube 270. Generally, when air passesthrough the laser beam produced by the laser, the particles cause laserscattering. The particle detector 260 analyzes the scattered laseremissions to identify particle concentration. In further examples, theparticle detector 260 includes a multichannel system, for example sixchannels, with each channel being configured to detect particles withina particular size range. Some of the particle size ranges of each of thechannels may overlap with the other channels. While the aspect of FIG. 2includes one particle detector 260, other aspects may include multipledetectors located throughout the factory interface. Additionally, it iscontemplated that the particle detector 260 is generally any suitableparticle detector.

As described above, the particle detector tube 270 of FIG. 2, as anexample, is a straight tube of any length. In one aspect, the tube lacksbending in order to align with the direction of the air stream throughthe FI 203 and to increase detection sensitivity. The particle detectortube 270 may include an opening at the top of the tube, i.e. the enddistal to the particle detector 260, and/or an opening along the lengthof the tube directed toward some location within the FI 203. In oneaspect, the opening is directed towards one of the load-lock slit doors240 a, 240 b to monitor particles coming from the area of the load-lockslit door 240 a or 240 b. In another aspect, the opening is below thesubstrate support 230 to monitor particles coming from the top of the FI203, such as particles that pass through the filter 220. In yet anotheraspect, the opening is directed towards the FI door 250 to monitorparticles coming from the FI door 250. While one particle detector tube270 is shown, the particle detector 260 may include a plurality ofparticle detector tubes 270 that are positioned within and open to orotherwise directed towards different locations within the FI 203.

As discussed above in the example of FIG. 2, the particle detector tube270, or plurality of particle detector tubes 270, are generallysubstantially straight between the end connected to the particledetector 260 and the opening at the position for particle detection.However, in order to open to different locations within the FI 203, theplurality of particle detector tubes can include various bends and turnsin order to reach the respective location; however, the opening willremain at a position configured to align with the direction of themovement of air through the FI 203. The different locations within theFI 203 for detection are generally selected to be those locations whichcan be used to most effectively capture the overall particlecontamination and movement within the FI 203 based on process andhardware considerations.

In the example shown in FIG. 2, the exhaust outlet 290 includes a baffleplate 291 having a plurality of holes 293 through which particles aredirected through a gas outlet and out of the Fl 203. The plate-and-holeconfiguration of the exhaust outlet allows air flow therethrough whilecapturing larger contamination, such as chipped or broken substrates,from undesirably entering the exhaust system.

FIG. 3 is a process flow 300 of continuous, in-situ particle detectionin an FI of a semiconductor manufacturing system, such as processingsystem 100. The process flow 300 begins by receiving a substrate in anFI through an FI slit door at operation 310. At operation 320, thesubstrate is transferred from the FI to a transfer chamber or a processchamber in the semiconductor manufacturing system through a load-lockslit door. Next, the substrate is transferred from the transfer chamberor the process chamber to a substrate support in the FI through theload-lock slit door at operation 330. More particularly, the substrateis transferred back into the FI from the transfer chamber or processchamber for post-processing cool down of the substrate. Oftentimes thesubstrate spends the longest period of time on the substrate support inthe FI for the post-processing cool down. As shown at operation 340,particle concentration in the FI is continuously monitored during thesubstrate transfer operations. Continuous particle monitoring allowsdetection of particles that exist or enter from opening the slit valvedoor, or that are carried in on the robot when grabbing the substrate.Thus, in addition to monitoring particles blown off the substrate by thefan during cool down, the present disclosure provides systems andmethods for monitoring particles at other times which occur in theabsence of a substrate being present.

In operation, continuously monitoring the particle concentration in theFI begins by directing air via the fan 210 towards the exhaust outlet290 to create a laminar flow. As shown in the vertical configuration ofFIG. 2, the fan 210 directs air downwards over the substrate support 230and particle detector 260 towards the exhaust outlet 290. In otherconfigurations, the fan 210 may direct air in a horizontal directionover the substrate support 230 and the particle detector 260. Theenvironmental air (e.g., air received the ambient environment within thefabrication facility) is first directed through the filter 220 to removeany particles from the air stream prior to entry into the FI below thefilter 220. When the substrate is positioned on the substrate support230, particles on the surface of the substrate will be entrained in theair stream and off the substrate surface. The air stream and entrainedparticles are then directed over the particle detector 260 as the airstream is directed towards the exhaust outlet 290. The air stream isreceived by the tube 270 and analyzed by the particle detector 260.

FIG. 4 is a slide showing a graph 400 of particle concentration detectedby a particle detector in an FI over time. The y axis corresponds toparticle count or concentration and the x axis corresponds to time, suchthat the graph 400 shows particle concentration in the FI over a periodof time. Data line 402 shows the particle concentration detected by aparticle detector such as the particle detector 260 of FIG. 2. Over afirst time period 404, the data line 402 is linear and shows little tono particle concentration in the FI 203. In other words, the data line402 over the first time period 404 shows that the FI 203 is running withlittle to no particle contamination. Over a second time period 406, theparticle concentration increases as shown by the peaks of data line 402.The particle concentration in the FI 203 may be the result of numerousevents, including but not limited to, reduced fan speed, a pressuredifference, an opening of the FI door, or a defective seal.

The data collected by the particle detector 260, such as the data shownin FIG. 4, can be delivered to a system monitoring server and combinedwith other data collected by other sensors in the factory interface,such as fan speed and pressure sensors, to identify the source of theparticle contamination. For example, if the data from the particledetector 260 shows that particle concentration increased over a periodof time, the server compares that data with data collected from asensor, such as a fan speed sensor, to see if the fan speed was reducedover the same period of time and caused the increased particlecontamination. The combined data can then be used to quickly identifythe root cause of the particle contamination and shorten the time toefficiently troubleshoot the semiconductor processing system.

In addition, the continuously collected particle detection data may beintegrated into a particle detection system 500, as shown in FIG. 5, andused to provide particle contamination alerts to equipment operators.The particle detection system 500 includes the particle detector 260 inthe FI 203, which is connected to a power source 510 and a server 520.The server 520 is generally connected to a network 530 forcommunication, for example, to equipment operators. Other FI detectorsmay also be connected to the particle detection system 500 to helpenable quick troubleshooting when the particle concentration is too highinside the FI 203. For example, in one aspect, one or more additionaldetectors can be positioned in the FI 203 and connected to the particledetection system 500. In another aspect, one or more additionaldetectors can be positioned in a second FI and connected to the particledetection system 500. Additionally, in further aspects, the particledetection system 500 is configured to send warning messages through thenetwork 530 when the particle concentration in the FI 203 exceeds apredetermined threshold value. The warning message may indicate theseverity of the particle contamination or underlying issue. It iscontemplated that different warnings and/or warning messages may beutilized depending on particle contamination severity.

Benefits of the described systems and methods for continuous, in-situparticle detection include, but are not limited to, reduced oreliminated system downtime during particle detection and increasedtroubleshooting efficiency due to the data collected by the particledetector being combined with other sensor data to identify the source ofparticle contamination to the FI. In addition, the systems and methodsdescribed herein result in increased process yield and decreasedsubstrate scrap rate.

While the foregoing contemplates positioning a particle detector withinthe FI, the particle detector may also be incorporated into other systemcomponents, including but not limited to, a load-lock or buffer chamber.

While the foregoing is directed to aspects of the present disclosure,other and further aspects of the disclosure may be devised withoutdeparting from the basic scope thereof, and the scope thereof isdetermined by the claims that follow.

The invention claimed is:
 1. A method for in-situ particle detection ina semiconductor manufacturing system, comprising: receiving a substratein a factory interface through a factory interface slit door;transferring the substrate from the factory interface to a transferchamber or a process chamber through a load-lock slit door; transferringthe substrate from the transfer chamber or the process chamber to asubstrate support in the factory interface through the load-lock slitdoor; and continuously monitoring particle concentration in the factoryinterface during the transferring the substrate from the factoryinterface to the transfer chamber or the process chamber through theload-lock slit door and from the transfer chamber or the process chamberto the substrate support in the factory interface through the load-lockslit door, wherein continuously monitoring particle concentrationcomprises: directing air via a fan over the substrate support and aparticle detector positioned downstream from the substrate support,receiving the air in a particle detector tube of the particle detector,introducing the air into the particle detector through the particledetector tube, and detecting a particle concentration in the air usingthe particle detector.
 2. The method of claim 1, further comprisingcooling the substrate during a post-processing cool down.
 3. The methodof claim 1, wherein continuously monitoring particle concentrationfurther comprises directing the air via the fan over the substrate whilethe substrate is on the substrate support.
 4. The method of claim 1,wherein continuously monitoring particle concentration further comprisesremoving one or more particles from the air by directing the air througha filter positioned between the fan and the substrate support.
 5. Themethod of claim 1, wherein continuously monitoring particleconcentration further comprises exhausting the air through a pluralityof holes formed in a baffle plate.
 6. The method of claim 1, furthercomprising: collecting particle concentration data from the particledetector; and communicating the collected particle concentration data toan equipment operator in the form of a warning message, the warningmessage indicating a severity of the particle concentration.
 7. Themethod of claim 1, wherein the directing the air via the fan comprisesdirecting the air in an airflow direction and into the particle detectortube of the particle detector, the particle detector tube being alignedin the airflow direction.
 8. The method of claim 1, wherein thedirecting the air via the fan comprises directing the air into theparticle detector tube of the particle detector, the particle detectortube extending upward from an upper surface of the particle detector andtowards the fan.
 9. The method of claim 8, wherein the particle detectortube includes one or more bends.
 10. The method of claim 1, wherein theparticle detector is positioned at a distance from the substratesupport, the distance being within a range of 1 inch to 24 inches.
 11. Amethod for in-situ particle detection in a semiconductor manufacturingsystem, comprising: receiving a substrate in a factory interface througha factory interface slit door; transferring the substrate from thefactory interface to a transfer chamber or a process chamber through aload-lock slit door; transferring the substrate from the transferchamber or the process chamber to a substrate support in the factoryinterface through the load-lock slit door; directing air via a fan overthe substrate support and a particle detector positioned downstream fromthe substrate support; receiving the air in a particle detector tube ofthe particle detector; introducing the air into the particle detectorthrough the particle detector tube; and detecting a particleconcentration in the air using the particle detector.
 12. The method ofclaim 11, further comprising cooling the substrate during apost-processing cool down.
 13. The method of claim 11, furthercomprising removing one or more particles from the air by directing theair through a filter positioned between the fan and the substratesupport.
 14. The method of claim 11, further comprising exhausting theair through a plurality of holes formed in a baffle plate.
 15. Themethod of claim 11, further comprising: collecting particleconcentration data from the particle detector; and communicating thecollected particle concentration data to an equipment operator in theform of a warning message, the warning message indicating a severity ofthe particle concentration.
 16. The method of claim 11, wherein thedirecting the air via the fan comprises directing the air in an airflowdirection and into the particle detector tube of the particle detector,the particle detector tube being aligned in the airflow direction. 17.The method of claim 11, wherein the directing the air via the fancomprises directing the air into the particle detector tube of theparticle detector, the particle detector tube extending upward from anupper surface of the particle detector and towards the fan.
 18. Themethod of claim 17, wherein the particle detector tube includes one ormore bends.
 19. The method of claim 11, wherein the particle detector ispositioned at a distance from the substrate support, the distance beingwithin a range of 1 inch to 24 inches, and the air is directed via thefan over the substrate support and the particle detector positioneddownstream from the substrate support to create a laminar flow.
 20. Themethod of claim 11, wherein the substrate support is positioneddownstream from the fan.
 21. The method of claim 11, further comprisingdrawing at least a portion of the air into the particle detector using apump of the particle detector.